Surgical retractors are devices that utilize tissue engaging members, such as retractor blades, to increase the size of an incision and provide access to a surgical site. Retractors permit a surgeon to retract soft tissues surrounding the incision and obtain a clear view of the operating site during a procedure. By retracting the tissue surrounding the incision to form an enlarged surgical channel, a relatively small incision may be used which minimizes trauma to the patient and shortens recovery time. However, existing surgical retractors continue to suffer from a number of shortcomings which make them difficult to use.
One such problem is the ability to easily adjust the depth of the retractor blades within an incision to avoid striking bones when the blades retract. A number of prior retractors attempt to solve this problem by providing upward and downward adjustment of the retractor blades. However, these systems are difficult to adjust and require tools to manipulate the position of the retractor blades. For example, U.S. Patent Application Publication No. 2007/0238932 to Jones et al. discloses a locking mechanism having a worm gear which adjusts the position of an associated retractor blade. The engagement between the worm gear and the retractor blade is under a high torque to inhibit unintentional movement of the retractor blade. To overcome this high torque and adjust the retractor blade position, a user inserts an elongate tool into the locking mechanism and rotates the tool about its longitudinal axis. As is apparent, this approach is time-consuming and requires a significant amount of tool rotation to individually adjust the retractor blades. Thus, a need exists for a retraction apparatus that is easier to use.
Another problem with existing surgical retractors is the difficulty involved with connecting or removing retractor blades. For example, U.S. Patent Application Publication No. 2007/0203399 to Gephart et al. discloses connecting a retractor blade to a retractor slider by biasing a locking pin against the retractor blade. Once the locking pin is aligned with one of a plurality of holes in the retractor blade, the locking pin projects into the hole to retain the retractor blade on the slider. To remove the retractor blade from the slider, an unlocking instrument is inserted into the retractor blade hole to push the locking pin out of engagement therewith. Similarly, the locking pin must also be pushed out of engagement before the retractor blade can be adjusted to a different depth within the incision. This approach is clearly problematic, as having to use an instrument to adjust or remove each retractor blade unduly prolongs surgery. Further, the plurality of holes in the retractor blade restricts the blade to a discrete number of positions along the slider, which limits the ability of a surgeon to adjust the blade depth to conform to a patient's anatomy. Therefore, a need exists for a retractor that permits removal and flexible adjustment of the retractor blades without the use of an additional tool.
Retracting soft tissue in close proximity to a bone poses yet another problem for standard surgical retractors because the retractor blades cannot retract the tissue toward the bone to position the surgical channel near the bone. For example, the U.S. Patent Application Publication to Jones et al. discussed above discloses a D-shaped retractor frame with a straight side that is aligned along a length of the spine. Support structures carry the retractor blades between unretracted and retracted positions, with the support structure of the straight side retracting along a path perpendicular to the straight side itself. With the retractor blades in the retracted position, the thickness of the straight side retractor blade and its connection to the support structure limit how far the surrounding tissue can be retracted toward the bone. Also, if the bone is elevated above the surrounding anatomy, the straight side support structure may strike the bone, which limits the size of the enlarged opening. Accordingly, an access retractor that may be placed adjacent a bone and used to enlarge an incision toward the bone without being limited by a retractor blade or its support structure would be desirable.